KR100269003B1 - In-situ stabilized compositions - Google Patents

Abstract

Insoluble particulate materials, which may be in solid or liquid form, are dispersed in a continuous non-aqueous phase and the dispersion rendered stable and resistant to phase separation by an in-situ stabilization procedure involving the formation of chemical bonds among the stabilizer components and to dispersed phases to form a network surrounding the particles which is compatible with the continuous phase. The invention has particular application for the formation of stabilized polyolefin-modified bitumen compositions for paving and other applications.

Description

[Name of invention]

In-situ stabilized composition

[Brief Description of Drawings]

FIG. 1 shows a high magnification of a sample of a bitumen-polyethylene composition prepared according to the method of Example 1, not according to the present invention, which is not according to the present invention, which shows the presence of polyethylene particles coalesced in bitumen as stored after storage for 3 hours at 160 ° C. without stirring. (x 1650) picture;

FIG. 2 is a high magnification (x1650) magnification of a sample of a polyethylene-bitumen composition stabilized against significant phase separation as obtained using the method of Example 3 according to the present invention and is a photograph after 3 days storage at 160 ° C. without stirring. .

FIG. 3 is obtained after repeated reheating of the sample three times from room temperature to 160 ° C. without stirring, obtained using the method of Example 3 according to the present invention, and high magnification of stable polyethylene-bitumen dispersion (x1650). It is a photograph.

[Field of Invention]

The present invention relates to stabilizing insoluble particulate matter in liquid phase by in-situ reaction.

[Notes on Related Applications]

This application is part of US Patent Application Serial No. 767,941, filed September 30, 1991.

[Background of invention]

It is often necessary to maintain insoluble solid particulates or immiscible liquid droplets in suspension in a continuous liquid phase for various purposes, and various emulsifiers have been used to achieve this result. One common use is emulsification of nonpolar liquid hydrocarbons in water, where each droplet of liquid hydrocarbons is separated due to the electrostatic repulsion of the emulsifier adsorbed on the droplet surface.

In non-aqueous emulsions there is no electrostatic force and therefore other methods should be used to prevent coalescence and separation of the dispersed phase. One particular area of the latter category is the provision of stable bituminous polymer compositions for use and related use as road surface asphalt. It is well known that certain properties of bitumen can be improved by addition of polymeric materials or by modification by polymeric materials. For example, European Patent Publication No. 317,025 to Shell Internationale Research Maatschappij BV discloses a reverse clearing composition useful for road pavement containing asymmetric radial block copolymers exhibiting increased hardness and adhesion. The recently published PCT Publication No. W090 / 02776 by Societe Nationale Elf Aquitaine discloses bitumen modified with binders such as copolymers of styrene, conjugated dienes and sulfur. Among the properties of bituminous compositions that can be possibly improved by dispersing polymer materials in the composition, especially in road use, are increased rutting resistance, enhanced low temperature cracking resistance, improved static friction, better adhesion / adhesion, and tensile strength. There are lifts and other benefits. However, a problem often encountered with bitumen-polymer mixtures is the incompatibility of bitumen and polymer components. Bitumen and most polymers, especially polyolefins such as polyethylene, do not readily blend with each other in the molten state. Dispersed molten polymer tends to aggregate and coalesce quickly, and dispersing of the bituminous composition tends not to be maintained. Once phase separation occurs, the possibility for improved properties is lost. One approach to overcome this problem is to use other additives to form stable bitumen gels, as described, for example, in US Pat. No. 4,018,730, assigned to McDonald's on April 19, 1977. This approach has the disadvantage of providing a thick or jellydized material, the higher viscosity of which has less desirable working characteristics than is desirable for the use of conventional bitumen.

Very closely related to the bituminous composition obtainable by the present invention is disclosed, for example, in US Pat. No. 4,314,921 (February 9, 1982 and assigned to Novophalt SA) and in German Patent 39 20 878 (January 4, 1990). And assigned to Novophalt SA). These documents disclose specific physical mixing methods to achieve homogenization of molten bitumen and thermoplastic polymers such as polyethylene. This unusual method of mixing appears to be necessary to date because it is difficult to obtain the proper dispersion of the polymer component in bitumen to provide the desired properties in the work material produced. As described in US Pat. No. 4,314,921, the shearing force of the polymer is necessary to obtain homogenization. In addition, homogenized bitumen and polymers tend to undergo significant phase separation even after such homogenization, requiring continuous stirring and preparation in situ or on-site. Thus, applying the Novophalt process described in this patent to a manufacturing site involves the addition of packaging components such as sand or gravel to the homogenized mixture within a relatively short time after the homogenization process is complete.

US Pat. No. 4,154,710 to Maldonado et al. (Issued May 15, 1979 and transferred to Elf Union) discloses modified bitumen by heating bitumen in the presence of polyisobutene, or A modified bitumen is disclosed by heating a bitumen in the presence of sulfur with a mixture of fatty acid esters consisting of natural extracts (ie esters of oleic acid, palmitic acid, stearic acid with higher alcohols such as lanosterol, cholesterol or isocholesterol). . Obviously stable mixtures were obtained by mixtures of polymers such as isobutene-butadiene copolymers, ethylene-cyclopentadiene copolymers and polybutene-polyisobutene copolymers.

Inventor Raymond T. Another approach to stabilizing dispersed polymer phases is described in Raymond T. Woodhams and assigned to U.S. Pat.No. 4,978,698. As described therein, the emulsifier system for providing a dispersed polyethylene phase consists of polyethylene wax having a molecular weight of about 1000 to about 10,000 and a terminal group having an acid group, in particular a carboxyl group. The inorganic metal oxide may also provide chemical association with the acid groups of the polyethylene wax. These compositions show stability, but it is often observed that phase separation occurs.

Other attempts to maintain polymer material dispersed in bitumen include the use of dispersants to improve compatibility between polymer and asphalt to prevent coalescence and phase separation. However, none of these approaches have succeeded as a viable commercial workflow. For example, various polymer modifiers used as dispersants tend to deposit in contact with the device in the packaging, causing serious packaging problems.

This prior art does not maintain stabilizing insoluble or incompatible polymer particles or droplets in liquid asphalt media by steric stabilization and also does not plan a system that resists phase separation at elevated temperatures for extended periods of time under stationary conditions as in the present invention. I couldn't.

[Overview of invention]

The present inventors now surprisingly find that, unlike the prior art, stable dispersions of insoluble polymers can be achieved in bitumen, which shows stability against phase separation in liquid media. This stability is achieved by using a novel in-situ stabilization method which leads to steric stabilization of the insoluble polymer particles as dispersed phase in bitumen as described below. This in-situ stabilization method does not limit its use for stabilization of insoluble polymer phase dispersed in bitumen, and is generally used for dispersion of insoluble organic fine particles in a non-aqueous continuous phase. One use of the present principles is the stabilization of polyolefin particles in lubricating oil to provide improved lubrication properties. Other articles of the composition wherein the present invention is useful include inks, paints, varnishes, cokes, sealants, coatings, roofing membranes, containment films, shingles, potting resins, Lubricants and greases. Thus, as one embodiment of the present invention, a continuous non-aqueous liquid phase; Dispersed particulate phases of insoluble organic substances in the liquid phase; And a steric stabilizer comprising a second component fixed to the particulate and bonded to the first component and the first component, the second component being soluble in the liquid phase, wherein the dispersed particulates in the particulate phase are mutually dispersed in the liquid phase. The separated state is maintained to prevent the dispersed fine particles from being separated from the liquid phase by gradual association. The particulate phase may be in the form of solid particles or droplets. The steric stabilizer component of the composition is formed by in situ chemical bonding between the steric stabilizer forming components and fixed to the particulate organic material, so that the partially crosslinked compound bond and the separated particulate phase are bonded to the liquid phase. To form a unique three-dimensional layer having.

[General description of the invention]

The present invention broadly relates to stabilization of insoluble fine particles in a non-aqueous continuous phase by in-situ forming chemical bonds and crosslinks between the non-aqueous continuous phase and the insoluble fine particles. The main applications of the present principles are stabilized polymers suitable for use in packaging materials for all packaging applications, including hot mixes, cut-backs, emulsions and crack fillers, and also suitable for other applications. In the provision of modified bituminous compositions.

The term "bitumen" as used herein refers to a kind of black or dark (solid, semisolid or viscous) cementitious material, natural or synthetic, most of which are high molecular weight asphalt, tar, pitch and asphaltenes. (asphalites) consist of typical hydrocarbons. The term "asphalt" as used herein refers to a dark, brown to black cementitious material, solid or semisolid, and the overwhelming component is bitumen obtained as a residue of bitumen or petroleum refining present in nature. Bitumen consists of the main continuous phase of a polymer-modified bitumen composition and the polymer is dispersed in bitumen as either solid particles or droplets, depending on the nature of the polymer and the temperature of the composition. The polymer component of the bitumen composition can be melted for dispersion in bitumen or consist of individual particulates and can be any polymer which gives it useful properties. In general, such polymer components consist of homopolymers and copolymers of ethylene and propylene, in particular homopolymers and copolymers of ethylene.

However, other polymeric materials, such as crumb rubber, may also be used. Substantially any grade of polyethylene polymer or copolymer will be used to provide the polymer component of the bituminous composition. One advantage provided by the present invention as used in bituminous-polyolefins and other such compositions is that mixed, recycled or waste polyolefins can be used to provide a dispersed polyolefin phase rather than requiring a pure material. To form a stable emulsion, bitumen is heated to a temperature above the melting temperature of polyethylene or other olefin polymers and then dispersed in bitumen by high shear mixing to form a uniform dispersed phase of the droplets in bitumen. When it stops, it will disperse in the presence of a stabilizer. However, any other conventional method for carrying out the dispersion on the particulate polymer may be used. The amount of polyethylene or other polymer dispersed in bitumen may vary greatly depending on the final desired properties and the end use purpose consistent with the composition. Generally, for road paving, the amount of polymeric material present in the composition varies from about 0.5 to about 10 weight percent of bitumen, preferably from about 2.5 to about 7 weight percent of bitumen. The emulsion is in-situ stabilized by a chemical reaction described in more detail below, while the bitumen is hot and the liquid droplets of polyethylene are constantly dispersed by the applied shear force. When this reaction is complete and the shear force is removed, the polyethylene-modified bitumen composition is stable at high temperatures in the range of about 100 ° C. to 200 ° C. without phase separation and without stirring. A photograph of a sample of the composition provided according to the invention is shown in Figure 2, where the dispersed nature of the small polyethylene droplets can be seen. This scene contrasts with the photograph of FIG. 1, which depicts the situation two or three hours after stopping agitation from the composition formed by high shear mixing and depicts an unstable state in accordance with the present invention. An additional advantage achieved by the steric stabilization of the polyethylene or other olefin polymers obtained here is that the small discrete particles of polyethylene can be adjusted to obtain different average particle sizes as needed and contribute significantly to the hardness of the packaging or other end use of the composition. It is spontaneously made by dispersion of a molten polymer having a particle size that may be less than 1 micron. It is noted that simple mixing does not achieve this small size even when high shear conditions are used, unless various dispersants are used to, for example, lower the interfacial tension and viscosity difference between the dispersed and continuous phases. The composition can also be cooled to ambient temperature, reheated up to about 160 ° C. or more than about 200 ° C. several times, and maintaining this high temperature for several days does not tend to phase separate. A photograph of a sample of the composition heated three times from room temperature to 160 ° C. is shown in FIG. 3. As shown, small polyethylene droplets are dispersed. This property is important because, unlike the state of presence of highly sheared unstabilized compositions, in situ formation of polyethylene modified bitumen compositions is not necessary. This emulsion is inherently stable due to chemical bonding and can be solidified and reheated without loss of uniformity or stability.

The present invention compositions may be formulated for use in a variety of ways. As discussed below, stabilized concentrates may be formed by in situ mixing of bitumen and polyethylene. Alternatively, compositions containing bitumen and stabilizer components may be provided, which are transferred to the site of use and added at the site of polyethylene. In addition, all components may be mixed in the same place to form a composition.

[Three-dimensional stabilization]

In order to stabilize the polyethylene or other olefin polymer dispersed in bitumen it is necessary to react the multiple components with each other and with the continuous and disperse phases.

Stabilization is achieved using a plurality of components. The first component is a bitumen-soluble component, which consists of a first part for bitumen, generally bitumen itself, and partly covalently bonded to a second part of the polymer compatible with the first part for bitumen. Bitumen-compatible organic polymers are generally alkenes and may be conjugated diene polymers or polydiene based copolymers. Preferably the bitumen-compatible organic polymer is a polydiene rubber having a molecular weight ranging from about 500 to about 60,000, more preferably a polydiene rubber having a molecular weight ranging from about 1,000 to about 12,000. Covalent bonding of bitumen-compatible polymers to bitumen can be carried out with or without reactive reagents of the kind that can generate free radicals, reagents such as peroxides or elemental sulfur, or accelerators and sulfur donors. The second component is a polymer component mixable on the dispersed polymer by being fixed in a stable dispersion and may also be covalently bonded as by nucleophilic bonding with the bitumen-compatible polymeric second portion of the first component. Nucleophilic bonds are derived from the reaction of an electrophilic atom such as carbonyl group carbon in an anhydride group with a functional group having nucleophilic heteroatoms such as O, N, or S.

Preferably the second component has a framework similar to the dispersed phase polymer and is generally polyethylene or other polyolefins, allowing the polymer chains of the second component to mix with and adhere to the melt dispersed polymer particles. The second component will have a molecular weight of about 10,000 to about 1,000,000, preferably about 50,000 to about 500,000. Covalent linkages of functionalized polymer components to bitumen-compatible organic polymers are generally provided on bituminous-compatible organic polymers, for example anhydrides on polymer components that can be mixed with the organic polymer with nucleophilic groups such as, for example, amino or carboxyl groups. It is carried out by reaction of an electrophilic period such as a carbonyl group present in the group.

In one specific embodiment of this invention, as the bitumen-compatible polymer, a polybutadiene or polybutadiene base copolymer partially functionalized with nucleophilic amino groups may be used, such as carboxylated polyethylene as a polymer component compatible with organic polymers. Functionalized polyethylene can also be used.

Other known nucleophiles include hydroxyl, carboxyl and sulfhydryl groups, and other known electrophiles include anhydrides, other carbonyl-containing groups, and epoxy and isocyanate groups. The amine-terminated poly (butadiene-co-acrylonitrile) of the examples used here for the purpose of illustrating the principle is a commercially available product. Butadiene copolymers containing other amine functionalized polydiene polymers and substantially polybutadiene components with, for example, styrene comonomers are suitable or more suitable and effective. In addition, high molecular weight polydiene polymers will be more desirable as long as they are soluble or compatible at the operating temperature.

Other well known covalent bonds may be used in this fact to join the bitumen-compatible polymer component and the polymer component. Such covalent bonds are obtained in other ways, for example as carboxylated polydienes and the carboxylated polyethylene may be bound by bifunctional aminol, diamine or diol. In addition to these components, liquid polybutadiene soluble in bitumen or compatible with bitumen may be provided as the third component of the stabilizer. In some cases polybutadiene or other polydienes may be omitted and the combination of functionalized polydiene and functionalized polymer is sufficient to carry out the reactions necessary to achieve steric stabilization. Butadiene or other chain extendable dienes or polymers have a molecular weight such that butadiene is soluble in bitumen or compatible with bitumen, and facilitates chain extension of butadiene upon crosslinking and free radical bonding with other components of the stabilizer. The molecular weight (Mw) range of this third component is low molecular weight, such as about 500, so long as the polybutadiene or copolymer thereof is soluble in bitumen at a mixing temperature, typically from about 150 ° C to about 200 ° C, or is compatible with bitumen. About 45,000 or more.

The components of the stabilizer composition are added to a stirred hot mixture of polyethylene and bitumen and then subjected to a free radical reaction using a free radical initiator such as sulfur. However, in view of viscosity in general, it is more practical to form pro-stabilizers from stabilizer components having pendant polymer chains. Upon substantial dispersion of the polymer in bitumen as a droplet at high temperature, the liquid polymer droplets absorb the suspended polymer chains, thereby allowing the stabilizing composition to adhere to the polymer particles to provide the gel envelope described below.

Polydiene rubber having a functional group and polyethylene having a functional group or a copolymer thereof have a covalent reaction in which one is bonded to the other. By initiation of free radical reactions between various polydiene components and reactive components in bituminous phases such as sulfur, polybutadiene undergoes a series of crosslinking reactions to form gel pores which greatly contribute to the stability of the dispersed polymer particles. Accordingly, the free radical reaction causes crosslinking of polybutadiene, crosslinking of polybutadiene to butadiene having functional groups, and binding to bitumen. The net effect of these different reactions is to form a network based on elongated polybutadiene of a chain having a partially crosslinked structure that is fixed to the polymer particles and swells in bitumen, resulting in the prevention of coalescence of the polymer particles. It is to form gel pores around the polymer particles. The various components of the steric stabilizer are polybutadiene-based layers having a crosslinked structure chemically linked to each other, fixed to the polymer particles, and swollen with a bitumen medium, thereby substantially fixing the polymer particles with each other in a continuous bitumen phase. To ensure a secure relationship. Layers based on polybutadiene are also fixed to bitumen. When molten, the particles are prevented from accessing or coalescing with each other by the gel lattice of the bonded polymer chains formed around the individual particles, which form a particle foreskin around the individual particles. When in solid form, the particles do not aggregate or settle for the same reason. The composition of the present invention may be produced by conventional methods. In one embodiment, carboxylated polyethylene, liquid polybutadiene (if desired) amino-terminated poly (butadiene-co-acrylonitrile) and sulfur elements may be dispersed in bitumen. In a typical hot mixed asphalt pavement, the preferred ratio of carboxylated polyethylene to bitumen is from about 0.1 to about 5% by weight, more preferably from about 0.3 to about 1% by weight, and the raw material of butadiene having amino functional groups The preferred proportion of the copolymer is about 0.1 to about 3% by weight, more preferably about 0.2 to about 1% by weight. The amount of liquid butadiene will preferably range from about 0.1 to about 10 weight percent, more preferably from about 0.4 to about 6 weight percent relative to bitumen. The amount of sulfur is preferably between about 0.1% and about 10% by weight of the total mixture, preferably about 0.2 to about 5% by weight. For other applications, for example roofing, the relative proportions of the components may vary. The four components are subjected to high voltage shear conditions at a temperature of about 100 ° C to about 250 ° C, preferably about 130 ° C to about 200 ° C for a suitable time, about 0.1 to about 3.5 hours, generally about 0.25 to about 1 hour. It is added to the heated bitumen under agitation to form a homogeneous composition, which may be called a concentrate. The use of a vacuum or inert gas may be advantageous in some cases. This concentrate constitutes one aspect of the present invention and will be transferred from the concentrate, additional bitumen and polyethylene to the formation of the final mixture. Thus, in this aspect of the invention bitumen to form a stable dispersion of olefin polymer particles in bitumen, consisting of bitumen compatible polymers dissolved in bitumen compatible components that act as pro-stabilizers and bonded to the olefin polymer material. To provide a vaginal composition. Such concentrates can be used in a wide range of applications of the present invention for the dispersion of insoluble organic phases in non-aqueous liquid phases. Polyethylene requiring dispersion in bitumen is added to the concentrate at high temperature with additional bitumen as needed, and stirring is continued until the polyethylene is dispersed in the system to form a stable polymer-asphalt composition. The suspended olefin polymer chains on the pro-stabilizer are absorbed by the molten polyethylene, whereby the stabilizer material is mixed to adhere to the polyethylene particles. The amount of polyethylene present in such compositions is preferably between about 0.1 and 20% by weight, more preferably between about 1 and about 5% by weight, for typical hot mix asphalt pavement use. Depending on the end use of the composition, more or less amounts of polyethylene or other dispersed polymer may be used.

The present invention thus provides a stable molten bituminous mixture having polyethylene particles that do not coalesce at high temperatures. Thus, the present inventors can stabilize a molten bituminous composition having a polyethylene additive with a stabilizer having a polyethylene moiety, while those skilled in the art will stabilize other compositions having the same type of polymeric additive stabilized against significant phase separation by this stabilizer. I discovered that I would understand what would be. In this regard, it is contemplated that the polymer fragment, which is capable of mixing with the molten polyolefin and mixing and sticking therein to form a stable droplet in the presence of a stabilizer, as shown in FIG. Polyethylene and poly (ethylene-co-vinyl acetate) are believed to be polymers of the same type.

Similarly, it will be apparent that the principles of the present invention are generally available for the formation of sterically stable dispersions of insoluble dispersed particulates in non-aqueous liquid continuous phases. What is required is a liquid-soluble or -compatible, crosslinkable polymer component as a component capable of binding to the liquid phase, a component capable of binding to the disperse phase, and a stabilized layer adhered to the dispersed phase particles and surrounding each dispersed phase particle.

It has been found that effective dispersion temperatures are obtained at temperatures of about 10 ° C. to 50 ° C. or higher of the polymer being dispersed, depending on factors such as polymer molecular weight, matrix viscosity, and shear force of mixing. Thus, a grade of polyethylene having a melting point of 100 ° C. to 135 ° C. may be dispersed at a temperature of about 100 ° C. to 250 ° C. Thus generally found low density, linear low density and high density polyethylene can be dispersed and stabilized by the stabilizers of the present invention. Most polyethylenes used in consumer products have a melting temperature in the acceptable range and polyethylene mixtures such as those obtained as pelletized, flake or powdered recycled materials are suitable for dispersion in bitumen, and Will be stabilized according to the invention. In particular due to the lack of stability of the polybutadiene above about 210 ° C. in air, the upper limit on the time and temperature used for dispersion of the polymer in bitumen will be determined according to the described embodiments of the present invention. However, if an inert gas such as nitrogen surrounds the mixing process, it is possible to disperse the polymer in bitumen at temperatures above 210 ° C.

The amount of stereostabilizing agent required to achieve the required stability depends on the amount of dispersion of the polymer, since the different butadienes with different cis and trans and vinyl contents may form distinct microstructures through separate crosslinked elongated chains. Depending on some factors such as the microstructure of the steric stabilizer formed, it is very small, generally less than about 2% by weight of bitumen. Depending on the field of use of the composition, the amount of stabilizer will vary by about 10% by weight. The cost of achieving stability is economically interesting.

Emphasis here is on the use of stabilized polyethylene modified bituminous compositions as packaging materials for all kinds of packaging, while stabilized bituminous compositions also contain preformed sidewalk bricks, roofing membranes, single, waterproofing membranes, waterproofing agents, cork, potting resins and Discover the field of use as a protective tip material. Pavement materials generally include aggregates such as ground stone, sand, etc., along with bituminous compositions. Similarly, other additives to the bituminous composition are used depending on the intended use of the invention composition. For example, roofing materials may be obtained by the addition of suitable fillers such as asbestos, carbonates, silica, wood fibers, mica, sulfates, clays, pigments and / or fire retardants such as chlorinated waxes. In the case of crack filler use, it is advantageous to add oxides. As mentioned above, the principles of the present invention are not limited to implementing stabilization of bitumen-polyethylene compositions and can be used to stabilize the dispersion of a wide variety of insoluble solid particulate materials in a wide variety of non-aqueous liquid materials.

In the following examples, samples of bitumen from two separate raw materials were used. To the extent that the properties of these materials are known, they are summarized in Table 1 below:

EXAMPLE

Example 1

This example illustrates the high shear mixing of conventional polyethylene and bitumen.

100 parts of asphalt (Petro-Canada Bow River, Penetration 290-see Table 1 above for properties) were heated to 150 ° C. in a 1 liter reactor. Then add 2 parts of low density polyethylene (Esso Chemicals LL-6101, Mn = 12,500 g mol ^-1 , M _W = 40,000 g mo l ^-1 , Melt Index 20) and high shear mixer (Brinkmann) for 30 minutes at 150 ° C. Dispersed in asphalt as liquid droplets melted with a polytron mixer). After stopping mixing, the dispersion of polyethylene droplets coalesced quickly, and a viscous polyethylene layer formed on the surface of the liquid asphalt and could not be easily redispersed. Lack of stability to significant phase separation even after high shear mixing is typical of polyolefin dispersion in asphalt. Rapid incorporation of molten polyethylene particles is shown in the photograph of FIG.

Example 2

This example illustrates the effect of polyethylene wax added to bitumen-polyethylene emulsion. 100 parts of asphalt (Petro-Canada Bow River, Penetration 290) were heated to 150 ° C. in a 1 liter reactor. Then 2 parts of low density polyethylene (Esso Chemicals LL-6101) and carboxylated polyethylene wax (Eastman Chemicals Epolene C-16, molecular weight = 8000 g mol ^-1 , density at 25 ° C = 0.908 g mol ^-1 , acid value = 5 0.5 parts) were added and dispersed as molten droplets with a high shear mixer as in Example 1. Fine dispersion of polyethylene droplets was obtained within 15 minutes in the presence of C-16 wax, but after stopping mixing the dispersion quickly separated into an easily observed phase and the viscous polyethylene surface layer was visible after standing for several hours. Although carboxylated polyethylene wax has shown a rapid dispersion of polyethylene in asphalt, this material does not clearly stabilize the dispersion for total phase separation once the mixing stops.

Example 3

This embodiment illustrates the present invention.

Carboxylated polyethylene (0.5 parts Du Pont Fusabond D-101 at 25 ° C. density = 0.920 g mol- ¹ , melt flow index = 11-18; anhydrous content = 0.07gg mol / kg of resin, base polymer linear Low density polyethylene) was dispersed in 25 parts asphalt (Petro-Canada Bow River, Penetration 290) at 150 ° C. for 30 minutes. Then liquid polybutadiene (Ricon 134, Colorado Chemical Specialties Inc, microstructure 80 ± 5% trans- and cis-, 20 ± 5%, 1,2-vinyl, molecular weight (Mw) = 12,000, acid value (KOH / g) = 0) 1.4 parts, liquid amine-terminated poly (butadiene-co-acrylonitrile) (ATBN) (10% acrylonitrile in liquid form, catalog # 549, Scientific Polymer Products Inc., amine equivalent = 1200 g / mol) 0.6 parts and 0.2 parts of elemental sulfur were added in this order and mixed under high shear for 2 hours at a temperature between 150 ° C and 170 ° C. To this stirred mixture additional 75 parts of asphalt (Bow River 290) and 3 parts of low density polyethylene (Esso Chemicals 6101, melt flow index 20) were added. After 5 to 20 minutes, the dispersion of the polyethylene was completed as a droplet and there was no visual change in the particle size after the stirring was completed. The preserved dispersed nature of the polyethylene droplets can be seen in the photograph of FIG.

Example 4

The method of Example 3 was repeated with 3 parts of high density polyethylene (Du Pont Sclair2914, melt flow index = 45, 25 ° C., density = 0.96 g mol ⁻¹ ) instead of 3 parts of low density polyethylene. As a result, the asphalt emulsion was stable at 160 ° C. for 3 days with no observable change in particle size or viscosity.

Example 5

The method of Example 3 was repeated using 0.5 parts of carboxylated polyethylene wax (Eastman Chemical Products Epolene C-16 wax, molecular weight 10,000 or less) instead of Du Pont Fusabond D-101 carboxylated polymer. This substitution also produced a stable emulsion at 160 ° C. This experiment shows that the carboxylated polyethylene component may have a relatively low molecular weight (wax having a molecular weight less than 10,000 g / mol) as in this example or may have a high molecular weight polymer (melt flow index 11-18) as in Example 3 Prove that there is.

Example 6

The method of Example 3 was repeated with Lloydminister 85-100 penetration grade asphalt (see Table 1 above for Petro-Canada Clarkson Refinery-properties) instead of Bow River 290 asphalt. The resulting emulsion was stable at 160 ° C.

EXAMPLES 7-9

The method of Example 3 was repeated at various ratios of the test reactants as shown in Table 1 (parts by weight) below. The compositions of Examples 7-9 were all found to be stable at 160 ° C. for at least 3 days. This example demonstrates that the viscosity and particle size of the suspended particles may be adjusted by appropriate control of the reactant concentration.

Example 10

The method of Example 3 was repeated without addition of 0.6 parts amine-terminus (poly (butadiene-co-acrylonitrile)). The resulting emulsion was markedly phase separated as evidenced by microscopic observation.

Example 11

The method of Example 3 was repeated without the addition of sulfur. The resulting emulsion was unstable for significant phase separation as evidenced by microscopic observation.

Example 12

The method of Example 3 was repeated without the addition of liquid polybutadiene. The resulting emulsion was unstable for significant phase separation as evidenced by microscopic observation.

Example 13

The method of Example 3 was repeated, and the sample was cooled to ambient temperature and then reheated several times to 160 ° C. The viscosity of the sample of polyethylene dispersion in asphalt did not change significantly. The reheated dispersed nature of the polyethylene droplets can be seen in the photo of FIG. The results of the foregoing Examples 1 to 13 are tabulated for convenience in the following Table 2.

It is also to be understood that the photographs of FIGS. 1 and 2 are bitumen-polymer compositions melted at high temperatures. The coalescing state shown in FIG. 1 illustrates a system with significant phase separation. Such a system thus exerts a different action over time than the form of the system shown in FIG. When dispersed, the FIG. 1 system initially provides a similar appearance to that shown in FIG. 2, but over time the particles that are noticeable in motion under a hot-stage microscope at 160 ° C. encounter the polymer droplets. Incorporation into the large polymer particles shown in FIG. On the other hand, in the system of FIG. 2 no coalescing of smaller particles appears into the larger particles as in FIG. The system of FIG. 1 has significant phase separation that is easily observed at larger magnifications while the system of FIG. 2 is stabilized against this significant phase separation. In addition, it is acceptable that the stabilized particles shown in FIG. 2 are in an order of about 0.1 to about 1 or 3 microns.

[Overview of invention]

In an overview of the present invention, the present invention provides a new stabilized non-aqueous liquid with dispersed particulate phase, specifically stabilized without separation of the polymer phase in liquid bitumen media at both ambient temperature and high temperature by the use of a unique steric stabilization system. Provided are polymer-modified bitumen compositions. Modifications are possible within the scope of the invention.

Claims (20)

(a) bitumen continuous phase; (b) dispersed particulate phase of the olefin polymer insoluble in the bitumen phase; and (c) a steric stabilizer, wherein the steric stabilizer is (c-1) a first component consisting of an olefin polymer bonded to the dispersed fine particles and (c-2) a bitumen phase soluble in the first component. The dispersed fine particles in the bitumen remain separated from each other in the bitumen so as to have a second component composed of bound polydienes, and to prevent the finely divided phase from being separated from the bituminous phase by gradually coalescing the dispersed fine particles. A composition in which an olefin polymer is stably dispersed in bitumen. A composition according to claim 1, wherein the bitumen consists of asphalt and the particulate phase consists of a homopolymer or copolymer of ethylene. The composition according to claim 1 or 3, wherein the first component and the second component of the steric stabilizer bind by interaction of a functional group attached to the component. (a) bitumen, and (b) A stabilizing composition comprising the steric stabilizer of claim 1 dissolved in the bitumen, and used to prepare the composition of claim 1. The stabilizing composition according to claim 4, wherein the olefin polymer of (b) of claim 1 is a homopolymer or copolymer of ethylene. (a) in the presence of a component forming a steric stabilizer comprising a first component which is an olefin polymer for bonding to the olefin polymer particles and a second component which is different from the first component, which is a polydiene soluble in bitumen. Dispersing the olefin polymer at a temperature higher than the melting temperature of the olefin polymer to form a dispersion containing fine particles in a bitumen in which the olefin polymer is insoluble; And (b) bonding the olefin polymer to the particles of the olefin polymer by binding to the particles of the olefin polymer while being chemically bonded by the interaction of functional groups in the components forming the steric stabilizer, to the particles of the olefin polymer, and compatible with bitumen; Forming an adult steric stabilizer and keeping the particles of the olefin polymer apart from each other in the bitumen so as to gradually associate the dispersed particles to prevent separation of the bitumen and the particulate phase. A method for preparing the composition of claim 1. 7. The method of claim 6, wherein the microparticles of the olefin polymer are homopolymers or copolymers of ethylene having a melting temperature at which the olefin polymer is melted and dispersed in the bitumen at a temperature of 120-190 ° C. 8. The method of claim 7, wherein the homopolymer or copolymer of ethylene consists of polyethylene having a melting temperature of 115-130 ° C. The method of claim 6, wherein the polydiene is a homopolymer or copolymer of butadiene, the olefin polymer comprises a homopolymer or copolymer of ethylene, and the combination of the components is the butadiene polymer And a reaction between the amine end of the phase and the carboxyl end of the ethylene polymer. The method according to claim 6, wherein additional bitumen is also added to the bitumen composition. (a) dissolving polybutadiene having amine end groups in bitumen; (b) dispersing the carboxylated olefin polymer in the bitumen; (c) The method for producing a stabilizing composition according to claim 6, wherein the polycarboxylate die having the carboxylated olefin polymer and the amine end group is reacted to bond the diene to the diene. 12. The polybutadiene having no amine end group is also dissolved in the bitumen and the poly butadiene having no amine end group is partially crosslinked with poly butadiene having an amine end group and itself. Way. 13. The method of claim 12, wherein the partial crosslinking is initiated by a free radical initiator. The method according to claim 13, wherein the free radical initiator is sulfur and sulfur accelerators are used in combination or not. 15. The method according to claim 14, wherein the carboxylated polyethylene, liquid polybutadiene without amine end groups, poly butadiene with amine end groups and elemental sulfur are produced at a temperature of 100 to 250 ° C. until a uniform composition is produced. Dispersion in bitumen by mixing for 2.5 hours. The method of claim 13, wherein the olefin polymer is a carboxylated olefin polymer, the poly butadiene has a molecular weight of 500 to 45,000, and is dissolved in bitumen at a mixing temperature of 150 to 200 ° C. Characterized in that it is compatible with bitumen. An olefin polymer is dispersed in a stabilizing composition obtained by the method according to any one of claims 11 to 16. A method for producing the composition of claim 1. 4. The composition of claim 3 wherein the olefin polymer having functional groups is carboxylated polyethylene and the polydiene having functional groups is a diene having amine ends. The composition according to claim 1 or 2, wherein the amount of the dispersed particulate phase is 0.1 to 20% by weight of the composition. The composition according to claim 1 or 2, wherein the amount of the first component is 0.1 to 5% by weight of the bitumen continuous phase, and the amount of the second component is 0.1 to 3% by weight of the bitumen continuous phase. .